1. Field of the Invention
The present invention is generally related to a fuel supply system for an internal combustion engine and, more particularly, to a fuel supply system that is able selectively to draw water away from a fuel reservoir and dispose of the water without adversely affecting the operation of the internal combustion engine.
2. Description of the Prior Art
It is well known that certain fuel reservoirs can collect water within a fuel supply as a result of several causes. Many different concepts have been developed to deal with the problem of water in a fuel reservoir.
U.S. Pat. No. 4,328,825, which issued to Bishai on May 11, 1982, describes a fuel tank water drain system. In a vehicle driven by a diesel engine, a sensor is activated by an accumulation of water in the fuel tank and another sensor is activated when the engine temperature is at a level, less than normal operating level, indicating that the vehicle and its fuel tank have been stationary for a period sufficient to permit separation of the fuel from the water in the tank. A solenoid is energized upon activation of both sensors and opens a drain valve to permit the water to be drained from the tank.
U.S. Pat. No. 4,519,349, which issued to Cheney on May 28, 1985, describes a water ejector fuel system. Apparatus for ejecting water from a fuel system having a fuel reservoir with a water trap which is open to a pump in the presence of water and closed in the absence of water is provided. The pump operates each time the engine is started to receive a charge of water and each time the engine is stopped to discharge the charge of water to the exterior of the reservoir.
U.S. Pat. No. 4,389,889, which issued to Larson on Jun. 28, 1983, describes an apparatus for detecting the presence of water in a fuel tank. The fuel level in the tank is determined by detecting the change in capacitance between a pair of electrodes positioned with a generally vertical orientation so that as the fuel rises in the tank, an increasing area of the plates is adjacent to the fuel. Since the presence of water in fuel is very undesirable, the apparatus also includes means for detecting this water before it can affect engine performance and before it can affect the accuracy of the fuel level indicating circuitry.
U.S. Pat. No. 4,296,723, which issued to Aldrich on Oct. 27, 1981, describes an engine fuel system with fuel/water separation. The system includes a fuel storage tank connected to a vacuum pump by a supply line, a fuel/water separator, a fuel lift pump, a fuel/water return line and a fuel injector pump or carburetor. The fuel/water separator includes a coalescer interposed between the fuel lift pump and the injector pump or carburetor to separate the water from the fuel. Water collects in the lowest portion of the separator housing, is removed through an orifice in the fuel/water return line, and is routed back to the fuel tank. With moderate levels of water contamination in the fuel tank the system prevents water from reaching the fuel injector pump or carburetor for an indefinite period of time. The separator housing is constantly drained wince the separator is under pressure. The system has a suitable detector to detect the water level in the fuel storage tank. Water may be removed from the fuel storage tank by temporarily converting a part of the water/fuel return line to a water outlet pumping line through a three-way valve.
U.S. Pat. No. 5,078,901, which issued to Sparrow on Jan. 7, 1992, describes an automatic fuel decontamination system and method. The invention provides a system for the automatic removal of contaminants such as water from the fuel supply of an internal combustion engine of the type including an auxiliary fuel tank. The system is automatically controlled and responsive to sensed contaminant levels in a contaminant removal mechanism and employs an existing fuel transfer pump to direct fuel around the auxiliary fuel tank through the contaminant removal mechanism. The pump additionally operates to provide a continuous supply of fuel to the engine to keep it operating while simultaneously permitting the discharge of contaminants from the contaminants removal mechanism when a predetermined maximum contaminant level has been reached. This system is especially effective in removing water from the fuel system of a diesel engine powered vehicle such as a tank wherein the engine and auxiliary fuel tank are components of a power pack that is removable from the tank.
U.S. Pat. No. 4,861,469, which issued to Rossi et al on Aug. 29, 1989, discloses a fuel tank dewatering apparatus. The dewatering apparatus is for insertion into and retrieval from an engine fuel tank through the tank inlet for removing water from the liquid fuel contained in the tank. The apparatus includes an elongate cylindrical container of fixed capacity and an elongate tie connected thereto and accessibly anchored near the fuel tank inlet. A volume of dry particulate hygroscopic material, principally cross-linked polyacrylamide co-polymer fills a minor portion of the container capacity and is expandable to many times its dry volume in the presence of water without absorbing the liquid fuel, so as to remove water therefrom within the capacity of the container. The dry volume is selected to limit the fully expanded volume to within the capacity of the container. The container is made of nylon or Delrin plastic and includes a rigid structural cage having spaced longitudinal and circumferential ribs, joined together with end closures and with a cylindrical screen contained within the cage for providing substantial porous wall surfaces exposed therebetween which are permeable to air, water and the liquid fuel but substantially impermeable to the hygroscopic material.
U.S. Pat. No. 4,809,934, which issued to Rix on Mar. 7, 1989, discloses an on-board disposal of water in aircraft fuel tanks. The system is adapted for the automatic extraction and dispersion of entrapped puddle of water in an aircraft fuel tank as a function of fuel flow supply to at least one propulsion engine. Scavenge pipes, positioned to be immersed in the puddles at their inlet openings, are connected to a venturi located within a fuel supply duct and arranged such that fuel drawn through the duct by means of a jet pump induces water extraction by suction at the venturi throat which is subsequently broken up within the jet pump and dispersed in the fuel.
U.S. Pat. No. 4,628,871, which issued to Glass on Dec. 16, 1986, discloses a fuel supply system for an internal combustion engine. The system has an intake manifold, an exhaust manifold, a carburetor and an air cleaner mounted on the carburetor. The system includes a heat exchanger in the exhaust manifold and a converter within the heat exchanger. An adapter plate is mounted on the intake manifold and the carburetor is mounted on the adapter plate. The adapter plate has passages providing communication between the carburetor and the intake manifold and with a metering valve mounted on the adapter plate. A main liquid fuel inlet line having a pressure regulator, a solenoid valve, a vacuum responsive pressure regulator and a vacuum controlled needle valve is connected to a fuel pump. The fuel inlet line is split into a primary fuel line and the secondary fuel line which are connected to the converter. The solenoid valve and a check valve are located in the secondary line and a check valve is located in the primary line. A water supply line having a pressure regulator, a solenoid valve, a fixed orifice restrictor and a check valve is connected to the converter. A vacuum controlled switch is connected to the converter. A vacuum controlled switch is connected to the intake manifold and is electrically connected to the solenoid valve in the secondary fuel line and the water supply line to open the solenoid valves when the vacuum in the intake manifold increases as the engine accelerates. A fuel vapor line connects the converter and the metering valve to supply fuel vapor and steam to the metering valve to mix with the air flowing through the carburetor to provide a hot fuel vapor, steam and air mixture to the intake manifold. The vacuum controlled switch is connected to the vacuum responsive pressure regulator and the vacuum controlled needle valve to provide increased fuel flow through the main fuel inlet line as the engine accelerates and the vacuum in the intake manifold increases.
U.S. Pat. No. 4,340,023, which issued to Creager on Jul. 20, 1982, describes a fuel supply and return system with a bypass valve and a water pumpout. The system is particularly useful with diesel fuel. The fuel is picked up through a fuel strainer system and pumped through a supply line to the engine. Excess fuel is returned to the fuel tank through a fuel return line. Since any water in the fuel separates from the diesel fuel and settles in the bottom of the tank, the water must at times be removed. By extending the fuel return tube to the bottom of the tank a siphon tube is provided which can be connected to a pump to pump out the water. If the water in the bottom of the tank freezes, a bypass valve in the upper portion of the fuel return line, but within the tank, operates so that returned fuel may still be discharged in the tank. Two flexible bypass valve arrangements are shown, both using variations of a duckbill valve to provide a closed valve when siphoning or pumping of the water takes place.
It would be significantly beneficial if an automatic means could be provided which removes water from a fuel/water separator without the need for intervention by an operator of the internal combustion engine.